Interior Minister Sheikh Rashid bin Abdullah al-Khalifa said: 'After widescale investigations and the inspection of various sites, the security forces arrested six people to stop them from carrying out grave acts against human lives and goods through the use of dangerous materials'.

The men's lawyer, Abdullah Hashim, said the men were seized in pre-dawn raids but said there were no 'activities calling for an arrest' and the reasons for their arrests were 'unclear'. The lawyer also confirmed that some of the men had previously been held for alleged links to Al-Qaeda but were released due to lack of evidence.

The suspects are believed to follow the extreme Sunni Salafi movement which is close to Osama bin Laden's Al-Qaeda. The men were named as Bassam al-Ali, Bassam Bukhowa, Yasser and Omar Kamal and Mohedin and Ali Khan.

Bahrain is home to the US Fifth Fleet and around 5,000 US expatriates live there, mainly military personnel.